Design Flows. Reading: Applied Hydrology, Sec 15-1 to 15-5. Hydrologic design. For water control Mitigation of adverse effects of high flows or floods Design flows for conveyance structures (storm sewers, drainage channels) and regulation structures (detention basins, reservoirs)
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Reading: Applied Hydrology, Sec 15-1 to 15-5
Q = peak discharge in cfs which occurs at tc
i = rainfall intensity in in/hr (duration used to compute i = tc)
A = watershed area in acres
C = runoff coefficient (0 ≤C ≤ 1)
An urban area consisting of sub-areas with different surface characteristics
Composite rational equation
j = number of sub-catchments drained by a sewer
Li is the length of the ith pipe along the flow path and Vi is the flow velocity in the pipe.
Valid for Q in cfs and D in feet. For SI units (Q in m3/s and D in m), replace 2.16 with 3.21.
Equation is valid for both SI and English system as long as the units are consistent
Compute tc and peak flow at D for i = 3.2 in/hr
Compute tc for AB and BC using Kirpich formula in the text (Table 15.1.2)
For CD, compute velocity by Manning’s equation and tc = length/velocity
Td = 30 min
QA (cfs) is pre-development peak discharge, A is watershed area (acres), C is runoff coefficient, Tp = tc (min), and Td is in min
Qp is the future peak discharge associated with Td
A = 96.6, b = 13.9, QA = 18 cfs, Tp = 20 min, A = 25 acre, C = 0.825
Td = 27.23 min
Detention storage is given by,
The volume of runoff after development = Qp*Td = 79, 140 ft3. Therefore, 53746/79140 = 68% of runoff will be stored in the proposed detention pond.
Next Generation 911
Geographic location by coordinates
Slide from: John BrosowskyProduct Development Director, GeoComm
Upper Brushy Creek (Round Rock)
City of Austin
We are all connected
Web services can play an important role in this……
I accessed this WaterML service at 7:10AM
And got back these flow data from USGS which are up to 6:00AM Central time
IBM is collaborating with UT….http://waterservices.usgs.gov/nwis/iv?sites=08158000&period=P7D¶meterCd=00060
…. to help build a Smarter Planet
Research Question: Can VLSI simulation models….. http://waterservices.usgs.gov/nwis/iv?sites=08158000&period=P7D¶meterCd=00060
….. be adapted to apply to river networks?
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Data and Mapping